1. Field of the Invention
The present invention relates generally to cleaning devices and, more particularly, but not by way of limitation, to devices utilized for stripping oil from a measuring tape used to measure the depth of oil in a tank and partially immersed in the oil for this purpose.
2. Brief Description of the Prior Art
Liquids, such as crude oil and the like, are commonly stored in large tanks and it is common practice for the quantity of liquid in a tank to be periodically measured. In many cases, this measurement is carried out by a workman who will visit the tank and make a direct measurement of the depth of the liquid it contains so that the volume of the liquid can be calculated. Access to the liquid is through a hatch at the top of the tank and the depth measurement is carried out by lowering a plumb bob, on the end of a measuring tape, through the hatch to the bottom of the tank. The liquid will coat that portion of the tape which enters the liquid so that the length of the coated portion of the tape, such length being given directly by markings on the tape, provides a direct measurement of the depth of liquid in the tank.
It is also common practice to monitor the quality of the stored liquid through sampling and, in some cases, it will be necessary to take samples at various depths in the liquid. For example, crude oil will stratify during storage so that, at times, it will be important to take a sample from a location near the bottom of the tank or from some other depth. The sample is taken by means of a container, commonly called a thief, which can be lowered to the desired depth at the end of a rope and which takes the sample at that depth.
It is, of course, necessary to clean the various implements used in measuring the depth of liquid in a tank and used for retrieving a sample from the tank after the use of these implements. It is generally not desired that oil be allowed to drip on the top of the tank nor is it desirable to a workman to carry an implement which is dripping oil. In the past, rags have often been used to wipe these implements but, because of the length of a measuring tape, such wiping is a tedious process. To avoid this wiping process, devices have been developed to automatically wipe a measuring tape as it is withdrawn from a tank. For example, U.S. Pat. No. 2,779,045, issued Jan. 29, 1957 to Harvey, discloses a device having a measuring tape, means for wiping the measuring tape as it is withdrawn from a tank, and a case for receiving the plumb bob on the end of the measuring tape. However, devices of this type have a couple of disadvantages. Such devices tend to be bulky and accordingly undesirable for transporting and, moreover, such devices provide for stripping of oil from the measuring tape outside the tank. On windy days, oil stripped from the measuring tape can be blown on to the top of the tank.